Search of MH370 enters new phase

The US Navy Captain Mark Matthews confirmed on Monday that searchers will begin to deploy the underwater autonomous vehicle, Bluefin-21, at about 5pm local time (0900 GMT) on Monday, marking a new phase in the search of the missing Malaysian flight MH370. [Special coverage]

[Read more: Underwater vehicle to be deployed in hours: MH370 search chief]

Matthews made the confirmation with Xinhua after the press conference hosted by Chief Coordinator of the Joint Agency Coordination Center Angus Houston.

Matthews said the Bluefin-21 underwater vehicle works in a 24- hour cycle, with two hours going down, 16 hours of searching underwater, two hours coming up to the surface and four hours for data downloading, analysis and re-programming.

He warned that once the Bluefin-21 is deployed, there will be no updates in at least 24 hours.

At the press conference, Houston said no pings had been detected since last Tuesday and it was now time for the next step in the search.

"(Australian navy ship) Ocean Shield will cease searching with the towed pinger locator later today and deploy the autonomous underwater vehicle Bluefin-21 as soon as possible," said Houston.

Houston said the failure to detect further signals may indicate that the batteries of the aircraft black boxes may have died 38 days after MH370 mysteriously disappeared en route from Kuala Lumpur to Beijing.

"It's time to go underwater," Houston said, stressing that the following process would be "slow and painstaking."

The Bluefin-21 underwater vehicle will initially cover an area of 40 square km. Using its sonar equipment, the mini-sub will send back a high-resolution 3D map of the ocean floor for analysts to sort out possible debris of the missing plane.

Captain Matthews introduced that the Bluefin-21 will conduct a survey scan of an area of 5 km by 8 km. It will use the side-scan sonar searching 300-400 meters in range and record acoustic returns of sonar transmissions.

The density of the silt at the bottom of the waters can complicated the search but Bluefin has the ability to scan through the silt.

Given the capacity of Bluefin-21 is 4,500 meters underwater, which is the approximately the depth of the waters in the area, Matthews said there is a possibility that other vehicles, both from U.S. Navy and some other sources, including private companies might be involved.

As a new encouraging lead, Ocean Shield discovered oil slick on Sunday in the search area where it had heard four signals possibly related to MH370.

But the source of the oil slick remained to be analyzed, Houston said.